Hi, daria. Although it’s a bit long in the tooth, I think Segaran, et al.’s Programming the Semantic Web has a lot of great beginner material (one can ignore all of the Python code and still get a lot out of the book). This book also looks promising, although I’ve not yet read it.
There are of course many great books on KG/linked data/semantic web, but they’re, by and large, not aimed at the beginner….